Towards all‐electrical spin injection and detection in GaAs

Abstract

We discuss our approach to realizing all-electrical spin injection and detection in GaAs via ferromagnetic metals and oxide tunnel barriers. A critical requirement is suppression of the formed Schottky barrier, which causes conductivity mismatching and prevents detection in reverse bias. However, initial I-V measurements of engineered GaAs/AlOx/CoFe tunnel contacts still show too high resistance area products in comparison to the semiconductor conductance, due to a large Schottky barrier contribution. To this end, optimized doping levels of the tunnel contacts and semiconductor spin transport region are calculated. Secondly, control over the magnetic properties of injector and detector electrode is established by designing both electrodes to have different switching fields, due to different widths.

Enhanced electrical spin injection and detection in biased lateral ferromagnet–semiconductor structures

“…Although injection of electrons is feasible when a voltage is applied across such a device, the presence of the Schottky barrier prevents tunnelling into the detector electrode in the reversed bias. However, by highly doping the region just beneath the semiconductor surface [8,26,27], numerical simulations show that the width of the Schottky barrier is much smaller than the spin flip length and comparable to the width of the insulating barrier resistance [28,29]. Therefore, it only affects electron transport across the barrier, i.e.…”

Magnetic Switching of Electrochemically Prepared Fe/GaAs Spin Contacts

“…Our ultimate goal is to use these contacts for spin injection and detection comparing them to those reported for Fe grown by vacuum techniques. [1][2][3] Efficient spin transport at a contact depends on the magnetic behaviour of the injector and detector contacts as well as the interfacial structure. These contacts must be designed in such a way that both have different magnetic switching fields.…”